Substrate-free gas-phase synthesis of graphene sheets

A method for synthesizing a graphene sheet, comprising:

• providing an atmospheric pressure microwave plasma reactor, said reactor having a plasma generator and an internal quartz tube, said quartz tube having an internal alumina tube;
• passing a continuous noble gas stream through the quartz tube;
• generating a plasma field within the quartz tube from said noble gas stream;
• aerosolizing a noble gas and ethanol to form ethanol droplets emitted from said internal alumina tube;
• directing said ethanol droplets through the quartz tube and directly into the argon plasma;
• wherein the ethanol droplets evaporate and dissociate in the plasma, forming solid matter;
• and
• rapidly cooling reaction products and collecting the reaction products on a membrane filter;
• wherein the collected reaction products comprise a plurality of graphene sheets.

A method for direct imaging of functionalized nanoparticles, comprising:

• providing a plurality of nanoparticles coated with surface molecules;
• producing a plurality of graphene sheets by passing liquid ethanol droplets through a plasma field;
• wherein the ethanol droplets evaporate and dissociate in the plasma field, forming graphene sheets;
• collecting the graphene sheets with a collector;
• applying the coated nanoparticles to a surface of said graphene sheets;
• and
• imaging said surface molecules on the surface of the nanoparticles the graphene sheets with an imager.